Our recent findings showed dramatic differences in the prevalence of Candida albicans colonization for urban an and rural human populations. In urban populations C. albicans represents 90-98 percent of oral yeast isolates, which is higher than is usually found. In contrast, in rural settings C. albicans represents less than 50 percent of oral yeast isolates. To our knowledge this situation is unique. The specific aim of this research proposal is to learn the genotypic and phenotypic methods developed and commonly used in the sponsor's laboratory in order to analyze and determine possible differences between populations of South African Candida spp. taken from urban and rural settings and to develop a monitoring system for better control of expected continuous rise in yeast infections and antifungal resistance in South Africa. We will also compare South African C. albicans yeasts to isolates from various geographic locales from the sponsor's laboratory collection as part of their global monitoring of C. albicans genotypes. The methods that will be used are: (i) DNA fingerprinting using the Ca3, Cg6, Ct14 and Cd25 probes for Candida albicans, Candida glabrata, Candida tropicalis and Candida dubliniensis respectively, (ii) analysis of all isolates and comparison with United States isolates using the Dendron software developed in the sponsor's laboratory, (iii) antifungal susceptibility testing of all isolates to determine the minimal inhibitory concentrations (MIC's). The long-term objective of this proposal is to transfer to South Africa the methodologies and expertise acquired during the fellowship in order to train post-graduate students and research assistants, and to develop research facilities focused on epidemiological studies of new opportunistic pathogens associated with AIDS. To date this has not been done in South Africa and the potential clinical implications make it a priority. Continued collaboration with the sponsor is envisaged with the exchange of data mutually beneficial to both countries.